Numerical study of unstiffened extended shear tab connections

• A finite element study on the bolt shear capacity of unstiffened extended shear tab connections
• The effective bolt eccentricity and connection capacity for several parameters were discussed.
• The effectiveness of the AISC manual 2011 design provisions was examined.
• The AISC design procedure was overly conservative for connections with 6 bolts or less in a single row configuration.
• When the finite element determined effective eccentricity was used, AISC procedure was markedly improved.

This paper presents the results of a numerical study on the behavior and strength of unstiffened extended shear tab connections using finite element modeling. The model was verified with the experimental results reported in the literature. The parameters studied included the web slenderness ratio of supporting member, distance between the center bolt line and weld line, plate thickness, number of bolts, double-row of bolts, and beam lateral restraint. Results were analyzed to determine the effects of these parameters on the behavior and bolt shear strength and also used to assess the effectiveness of the AISC manual 2011 design procedure. It shows that the AISC design procedure for bolt shear fracture was overly conservative for extended shear tab connections with number of bolts less than 6 in a single row configuration. For connections with 6 bolts or higher or double-row bolts, the AISC design procedure provided reasonably good estimate. When the AISC design procedure was used but in combination with the finite element determined effective eccentricity, the estimate on bolt shear strength was markedly improved, especially for connections with less than 6 bolts in a single row configuration.